Providing Optical Power Information from an Optical Receiver to an Optical Transmitter Using a Serial Bus

ABSTRACT

An optical receiver, within a first device, may receive first configuration information from an optical transmitter, also within the first device. While receiving the first configuration information, the optical receiver may operate according to a clock. Later, the optical receiver may receive optical data from a second device according to the first configuration. While receiving the optical data from the second device, the optical receiver does not operate according to the clock, wherein the optical receiver not operating according to the clock allows the optical receiver to receive the optical data with greater sensitivity.

PRIORITY INFORMATION

This application claims benefit of priority of U.S. provisionalapplication Ser. No. 61/535,817 titled “Alignment of Optical Sensors”filed Sep. 16, 2011, whose inventors were Tony Susanto, Zhonghong Shen,Tihsiang Hsu, Markus N. Becht, Galin I. Ivanov and Evan L. Marchman,which is hereby incorporated by reference in its entirety as thoughfully and completely set forth herein.

FIELD OF THE INVENTION

The present invention relates to the field of data communications, andmore particularly to optical communication between devices.

DESCRIPTION OF THE RELATED ART

In recent years communication between devices has become both prevalentand necessary. In some systems, devices may communicate via opticalmeans, e.g., using optical cables and optical transceivers. In somecases, these devices may communicate in a ring network, where data froma source device to a destination device may pass through severalintermediate devices. Each device may analyze the data to determinewhether or not data in the transmission is targeted to itself and eitheraccept that data or pass it to the next member in the ring.

In such configurations, and in data communication in general, the signalto noise ratio may be very low. Accordingly, distinguishing the datafrom the noise may be difficult. Accordingly, improvements in datatransmission and reception are desired.

SUMMARY OF THE INVENTION

Various embodiments of a system and method for performing opticalcommunication are presented below.

An optical transceiver may be included in a first device, e.g., as achip within the first device. The optical transceiver may be coupled toa controller or network interface chip of the first device. The firstdevice may be coupled to several other devices in a network, e.g., aring network. In one embodiment, the first device may communicate withthe other devices within the network uses optical signals. Thus, opticaldata on the network may be received and transmitted by the transceiverof the first device. The transceiver may include a transmitter and areceiver.

At a first time, e.g., during or proximate to a power up of thetransceiver or first device, the transmitter may provide configurationinformation to the receiver. For example, the transmitter may determinethat the receiver is powered, and may then provide configurationinformation to the receiver. In one embodiment, the transmitter mayprovide the configuration information using a serial bus, e.g., wherethe transmitter and receiver each have a respective serial peripheralinterface (SPI). During this transmission, the receiver may operate orreceive the data using a clock, e.g., which is provided by thetransmitter over the serial bus. Additionally, during this transmission,various oscillations (e.g., digital oscillations), electronic statechanges (e.g., digital state changes), flip flop transitions, etc. mayoccur for the receiver.

During and/or after transmission, the receiver may configure itselfaccording to the received configuration. For example, in one embodiment,the transmission may result in storage of the configuration informationin various registers (e.g., configuration registers) of the receiver. Inone embodiment, the data for each register may be provided on each clocksignal. Accordingly, the receiver may only configure itself if thenumber of clock signals match the number of registers.

After configuration, the receiver may receive optical data, e.g., fromanother device on the network. While receiving the optical data, thereceiver may operate “quietly”. For example, the receiver may notreceive the clock from the transmitter while receiving the optical data.In one embodiment, no (or limited) oscillations (e.g., digitaloscillations) may occur on the receiver while receiving the optical dataor subsequent to the transmission of configuration information from thetransmitter. Additionally, or alternatively, no state changes (e.g.,digital state changes), flip flop transitions, analog to digital ordigital to analog conversions, etc. may occur on the receiver so that itmay receive and detect optical signals of the optical data with greatersensitivity.

While the above is discussed with respect to an initial configuration(e.g., based on calibrations that may have been performed duringtesting), configurations may also be provided at other times, e.g.,during operation, such as in response to changes to the quality ofreceived optical signals. For example, in response to a change inquality of the optical signals, a second configuration may be receivedand used by the receiver. Accordingly, during reception a noisierenvironment may be required (e.g., as a result of using the clockprovided by the transmitter), but may become quiet after thetransmission is complete. The new configuration may be based on acalibration procedure, e.g., determined by the receiver, transmitter,and/or controller based on current conditions. Thus, configurations maybe provided to the receiver during operation, e.g., in a dynamicfashion.

The receiver may also be configured to provide information indicatingoptical power (e.g., of currently received optical signals) to thetransmitter. For example, the receiver may include an analog interfacewhich is able to provide an analog signal indicating the current opticalpower to the transmitter. In some embodiments, this transmission mayoccur over a serial bus using respective SPIs.

The transmitter, in turn, may provide an indication of the optical powerto the controller or network interface chip of the first device. Forexample, the transmitter may receive the analog signal (e.g., indicatedby a voltage or current) and perform analog to digital conversion togenerate a digital signal that indicates the optical power. Accordingly,the transmitter may provide the digital signal to the controller ornetwork interface chip of the first device.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present invention can be obtained when thefollowing detailed description of the preferred embodiment is consideredin conjunction with the following drawings, in which:

FIG. 1 illustrates an exemplary ring network for a set of devices,according to one embodiment;

FIG. 2 illustrates an exemplary system block diagram of a portion of adevice, according to one embodiment;

FIGS. 3 and 4 are block diagrams of exemplary transceivers, according toone embodiment; and

FIGS. 5 and 6 are flowchart diagrams illustrating embodiments of methodsrelated to performing optical communication.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and are herein described in detail. It should beunderstood, however, that the drawings and detailed description theretoare not intended to limit the invention to the particular formdisclosed, but on the contrary, the intention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the present invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION Terms

The following is a glossary of terms used in the present application:

Memory Medium—Any of various types of memory devices or storage devices.The term “memory medium” is intended to include an installation medium,e.g., a CD-ROM, floppy disks 104, or tape device; a computer systemmemory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM,Rambus RAM, etc.; a non-volatile memory such as a Flash, magnetic media,e.g., a hard drive, or optical storage; registers, or other similartypes of memory elements, etc. The memory medium may comprise othertypes of memory as well or combinations thereof. In addition, the memorymedium may be located in a first computer in which the programs areexecuted, or may be located in a second different computer whichconnects to the first computer over a network, such as the Internet. Inthe latter instance, the second computer may provide programinstructions to the first computer for execution. The term “memorymedium” may include two or more memory mediums which may reside indifferent locations, e.g., in different computers that are connectedover a network.

Carrier Medium—a memory medium as described above, as well as a physicaltransmission medium, such as a bus, network, and/or other physicaltransmission medium that conveys signals such as electrical,electromagnetic, or digital signals.

Programmable Hardware Element—includes various hardware devicescomprising multiple programmable function blocks connected via aprogrammable interconnect. Examples include FPGAs (Field ProgrammableGate Arrays), PLDs (Programmable Logic Devices), FPOAs (FieldProgrammable Object Arrays), and CPLDs (Complex PLDs). The programmablefunction blocks may range from fine grained (combinatorial logic or lookup tables) to coarse grained (arithmetic logic units or processorcores). A programmable hardware element may also be referred to as“reconfigurable logic”.

Hardware Configuration Program—a program, e.g., a netlist or bit file,that can be used to program or configure a programmable hardwareelement.

Computer System—any of various types of computing or processing systems,including a personal computer system (PC), mainframe computer system,workstation, network appliance, Internet appliance, personal digitalassistant (PDA), television system, grid computing system, or otherdevice or combinations of devices. In general, the term “computersystem” can be broadly defined to encompass any device (or combinationof devices) having at least one processor that executes instructionsfrom a memory medium.

Optical Device—any of various devices which are capable of performingoptical communication.

Automatically—refers to an action or operation performed by a computersystem (e.g., software executed by the computer system) or device (e.g.,circuitry, programmable hardware elements, ASICs, etc.), without userinput directly specifying or performing the action or operation. Thusthe term “automatically” is in contrast to an operation being manuallyperformed or specified by the user, where the user provides input todirectly perform the operation. An automatic procedure may be initiatedby input provided by the user, but the subsequent actions that areperformed “automatically” are not specified by the user, i.e., are notperformed “manually”, where the user specifies each action to perform.For example, a user filling out an electronic form by selecting eachfield and providing input specifying information (e.g., by typinginformation, selecting check boxes, radio selections, etc.) is fillingout the form manually, even though the computer system must update theform in response to the user actions. The form may be automaticallyfilled out by the computer system where the computer system (e.g.,software executing on the computer system) analyzes the fields of theform and fills in the form without any user input specifying the answersto the fields. As indicated above, the user may invoke the automaticfilling of the form, but is not involved in the actual filling of theform (e.g., the user is not manually specifying answers to fields butrather they are being automatically completed). The presentspecification provides various examples of operations beingautomatically performed in response to actions the user has taken.

FIG. 1—Exemplary Ring Network

FIG. 1 illustrates an exemplary ring network 100 having a plurality ofdevices coupled together in a ring arrangement. More specifically, thenetwork 100 of FIG. 1 is an exemplary network involving a plurality ofaudio devices, e.g., within an automobile. As shown, the network 100includes a receiver 102 coupled to right front speaker 104, which is inturn coupled to right rear speaker, which is in turn coupled to subwoofer 108, which is in turn coupled to left rear speaker 110, which isin turn coupled to left front speaker 112, which is also coupled to thereceiver 102.

In the exemplary embodiment of FIG. 1, the network 100 may be an opticalnetwork where each device communicates over the network 100 usingoptical communication. For example, each device may be coupled to itsneighboring devices using an optical connection, such as optical fiber.

In one embodiment, the network 100 may be a MOST network that utilizesthe MOST application framework. Generally, a MOST network may have amaximum of 64 nodes per ring, a maximum distance of 10 m between twonodes, and may be used in a point-to-point optical network, e.g., suchas shown in FIG. 1. The MOST application framework is a set of objectoriented, reusable components to design multimedia systems in automotiveenvironment, but also in similar other application areas. In aclassically wired system, each device may be controlled by an individualcable, such that the wiring harness will grow with each new device thatis added to the system. Accordingly, the devices each have proprietaryconnections and systems. These proprietary systems force a controllingdevice to handle many different interfaces and protocols.

In a networked system, such as in FIG. 1, each device may be identifiedby a unique address and shares various data with a common connection.Devices can be controlled by a dedicated master (e.g., the receiver102), but can also exchange information with each other. An advantage ofa networked system is that the communication paths are defined.Therefore, developers can focus on the product functionality instead ofcontinuously adapting their interfaces to the HMI.

The MOST application framework is independent from devices and network,allows use of functional modeling (e.g., fblocks, functions, etc.),provides hierarchical system management (e.g., masters, controllers,slaves, etc.), provides service discovery and plug and play mechanisms,provides modularity and reusability (e.g., of (blocks), and may providefree partitioning and easy repartioning (e.g., of fblocks), among otheradvantages.

In the exemplary network 100 of FIG. 1, audio data may be provided fromthe receiver to the left front speaker 112 and/or the right frontspeaker 104. The audio data may include data for one or more (or eachof) the right front speaker 104, the right rear speaker 106, the subwoofer 108, the left rear speaker 110, or the left front speaker 112.Accordingly, the right front speaker 104 may receive the audio data overthe network, determine if any portion of the audio data is addressed orintended for the right front speaker 104 and pass the data on to rightrear speaker 106, which may perform the same operations, continuingthrough the rest of the devices in the network 100. Alternatively, oradditionally, the same procedures may be performed starting with theleft front speaker 112 through the right front speaker 104 in theopposite direction. In various embodiments, the directionality of datamay be clockwise, counter-clockwise, or both in the ring network 100.

While FIG. 1 shows a typical ring network, note that in various otherembodiments, different networks may be used. For example, the network100 may be configured as a star network (e.g., having a centralizedcontroller or hub) or may be a hybrid network, e.g., where a portion ofthe network uses a star configuration and another portion uses a ringconfiguration. Additionally, the particular devices and implementationsof FIG. 1 are exemplary only. Virtually any type of devices may be usedin a ring network, instead of, or in addition to, the audio devicesshown in FIG. 1. For example, the devices in the network could includevideo devices, GPS devices, cameras, driver assist devices, CD changers,cell phones, tablets, computer systems, are any desired device. Thus,the network may be used to transmit any of a plurality of differenttypes of data, such as video data, GPS data, driver assist data, etc.Thus, the network 100 and devices shown in FIG. 1 are exemplary only andmay be implemented according various different configurations and mayinclude any of a variety of desired devices.

Thus, FIG. 1 is an exemplary network which includes devices that mayoperate as described herein.

FIG. 2—Exemplary Block Diagram of a Device

FIG. 2 illustrates an exemplary block diagram of a device 200, e.g.,which may be included in the network 100. More specifically, the blockdiagram of FIG. 2 may apply to any of the devices shown in FIG. 1.

As shown, the device 200 may include a network interface chip 210 and afiber optic transceiver 250. As also shown, the fiber optic transceiver250 may include a transmitter 260 and a receiver 270, which are coupledto each other. As also shown, the fiber optic transceiver 202 may becoupled to the network interface chip 208 via one or more lines or pins.More specifically, there may be two LVDS lines from the networkinterface chip 208 and two LVDS lines from the fiber optic transceiver202. Additionally, there may be a bidirectional line between thetransmitter 204 of the fiber optic transceiver 202 and the networkinterface chip 208 which may provide STATUS information.

FIGS. 3 and 4—Fiber Optic Transceiver 250

FIG. 3 illustrates one embodiment of a more detailed block diagram ofthe fiber optic transceiver 250. As shown, the transceiver includes thereceiver 270 (e.g., implemented as a first chip), which may beimplemented as a sensitive optical receiver, and the transmitter 260(e.g., an LED driver). In one embodiment, the receiver 270 andtransmitter 260 may be comprised within the same optical assembly alongwith a photodiode and LED.

As shown, the receiver 270 and the transmitter 260 are coupled via aserial bus. More specifically, the receiver includes a serial peripheralinterface (SPI) 272 which is coupled to the SPI 262 of the transmitter260. In this particular embodiment, the SPIs 272 and 262 communicateusing three lines from the SPI interface 262 to the SPI interface 272,one for SCLK (serial clock), one for MOSI (e.g., for data), and one forSS (slave select). As was shown in FIG. 2, the transmitter may bedirectly coupled to the network interface chip 210, while the receiver270 may not.

Thus, this system allows the two chips to transfer serial data betweenthem across a SPI (e.g., a 3 pin SPI). As discussed below, the receiver270 may be configured to receive important settings from the transmitter260 that is also configured to serially communicate with the networkinterface chip 210. The network interface chip 210 may be configured toserially send and receive data to and from the transmitter 260 (e.g.,via the serial_I/O pin), which can then serially shift importantsettings data to the receiver 270. Since the chip to chip transactionmay be performed rarely, the receiver 270 can remain quiet of digitalnoise and optimize receive sensitivity while monitoring the photodiode.More specifically, in one embodiment, the receiver 270 may not performanalog to digital conversion and/or digital to analog conversion (e.g.,it may not have circuitry that is able to perform such conversions orsuch circuits may not be utilized), may not receive clock signals (e.g.,from the transmitter 260), may not generate clock signals (e.g., it maynot be configured to generate clock signals), may not have statetransitions (e.g., such as digital state transitions), may not have flipflop toggling, etc. during normal operation, such as while receivingoptical data from devices on the network 100.

FIG. 4 illustrates another embodiment of a more detailed block diagramof the fiber optic transceiver 250. In this embodiment, the receiver 270may be configured to determine optical power being received by aphotodiode. The analog interface 472 may be configured to provide thispower reading, e.g., via voltage or current, to the transmitter 260,e.g., via serial I/O interface 462. In the embodiment of FIG. 4, thetransmitter 260 may be configured to perform analog to digitalconversion of this information and communicate the resulting digitalinformation to the network interface chip 210 through a serial I/O pin(e.g., the STATUS line shown in FIG. 2). Accordingly, the noisytranslation of the optical power signal to digital domain may beperformed by the transmitter 260 rather than the receiver 270, therebyallowing the receiver 270 to remain quiet and be better able totranslate sensitive optical inputs from the photodiode, e.g., withoutinterference from digital oscillations.

Note that the embodiments of FIGS. 3 and 4 may be implementedseparately, or may be combined, as desired. For example, the analoginterface 472 of FIG. 4 may utilize the SPI interfaces shown in FIG. 3to perform communication. Additionally, or alternatively, the analoginterface 472 may be combined or included as a part of the SPI interface272, as desired. Similarly, the serial I/O interface 462 may beimplemented as (e.g., all or a portion of) the SPI interface 262. Forexample, the SPI interfaces 272 and 262 may be modified to include anadditional line for providing the optical power information from thereceiver 270 to the transmitter 260.

FIG. 5—Configuring an Optical Receiver

FIG. 5 illustrates a method for configuring an optical receiver. Themethod shown in FIG. 5 may be used in conjunction with any of thecomputer systems or devices shown in the above Figures (e.g.,particularly with respect to FIG. 3), among other devices. In variousembodiments, some of the method elements shown may be performedconcurrently, in a different order than shown, or may be omitted.Additional method elements may also be performed as desired. As shown,this method may operate as follows.

In 502, at a first time, the transmitter may provide configurationinformation to the receiver. In one embodiment, the first time may occurduring or proximate to (e.g., within a few seconds of) a power up of thetransceiver or the device that includes the transceiver. For example,the transmitter may determine that the receiver is powered, and may thenprovide configuration information to the receiver. Note thatconfiguration information may also be provided at other times, e.g.,during operation, as discussed in more detail below.

In one embodiment, the transmitter may provide the configurationinformation using a serial bus, e.g., where the transmitter and receivereach have a respective serial peripheral interface (SPI), such as theembodiment shown in FIG. 3. During this transmission, the receiver mayoperate or receive the data using a clock, e.g., which is provided bythe transmitter over the serial bus. Additionally, during thistransmission, various oscillations (e.g., digital oscillations),electronic state changes (e.g., digital state changes), flip floptransitions, analog to digital or digital to analog conversions, etc.may occur for the receiver. Said another way, the transmission may causethe receiver to be “noisy” which would impeded sensitive measurements ofoptical signals during normal operation.

In 504, during and/or after transmission, the receiver may configureitself according to the received configuration. For example, in oneembodiment, the transmission may result in storage of the configurationinformation in various registers (e.g., configuration registers) of thereceiver. The receiver may use this data to configure itself. In oneembodiment, the data for each register may be provided on each clocksignal. Additionally, the receiver may only configure itself if thenumber of clock signals match the number of registers. Alternatively,the receiver may be automatically configured without any further actionsbased on the data being stored in the registers.

In 506, after configuration, the receiver may receive optical data,e.g., from another device on the network. While receiving the opticaldata, the receiver may operate “quietly”. For example, the receiver maynot receive the clock from the transmitter while receiving the opticaldata. In one embodiment, no (or limited) oscillations (e.g., digitaloscillations) may occur on the receiver while receiving the optical dataor subsequent to the transmission of configuration information from thetransmitter. Additionally, or alternatively, no state changes (e.g.,digital state changes), flip flop transitions, analog to digital ordigital to analog conversions, etc. may occur on the receiver so that itmay receive and detect optical signals of the optical data with greatersensitivity. In one embodiment, all of the circuitry that the receivermight normally have which cause the receiver to be “noisy” (such asanalog/digital conversion circuitry) may be shifted to the transmitterin order to allow the receiver to be more sensitive. Thus, duringoperation, the transmitter may include the “noisy” circuitry, whileallowing the receiver to operate quietly and with greater sensitivity.

While the above is discussed with respect to an initial configuration(e.g., based on calibrations that may have been performed duringtesting), configurations may also be provided at other times, e.g.,during operation, such as in response to changes to the quality ofreceived optical signals. For example, in response to a change inquality of the optical signals, a second configuration may be receivedand used by the receiver. Accordingly, during reception a noisierenvironment may be required (e.g., as a result of using the clockprovided by the transmitter), but may become quiet after thetransmission is complete. The new configuration may be based on acalibration procedure, e.g., determined by the receiver, transmitter,and/or controller based on current conditions. Note that the receivermay need to enter a calibration or configuration state (e.g., stopreceiving optical data) in order to receive the new configuration. Afterthe new configuration is received, the receiver may continue to receiveoptical data from the network. Thus, configurations may be provided tothe receiver during operation, e.g., in a dynamic fashion.

FIG. 6—Providing Optical Power Information

FIG. 6 illustrates a method for providing optical power information. Themethod shown in FIG. 5 may be used in conjunction with any of thecomputer systems or devices shown in the above Figures (e.g.,particularly with respect to FIG. 4), among other devices. In variousembodiments, some of the method elements shown may be performedconcurrently, in a different order than shown, or may be omitted.Additional method elements may also be performed as desired. As shown,this method may operate as follows.

In 602, a receiver may receive optical data from an external device(e.g., from another device within a common network, such as the oneshown in FIG. 1). In one embodiment, the receiver may have beeninitially configured in the manner described above, e.g., with respectto FIG. 5.

In 604, the receiver may determine optical power of one or more opticalsignals of the optical data. More specifically, the receiver may havemeasurement circuitry which is able to measure the optical power of thereceived optical signals.

In 606, the receiver may provide information indicating optical power(e.g., of currently received optical signals) to the transmitter. Forexample, the receiver may include an analog interface which is able toprovide an analog signal indicating the current optical power to thetransmitter. In some embodiments, this transmission may occur over aserial bus using respective SPIs.

The transmitter, in turn, may provide an indication of the optical powerto the controller or network interface chip of the first device. Forexample, the transmitter may receive the analog signal (e.g., indicatedby a voltage or current) and, in 608, perform analog to digitalconversion to generate a digital signal that indicates the opticalpower. Accordingly, in 610, the transmitter may provide the digitalsignal to the controller or network interface chip of the first device.These signals may be used by the controller or network interface chipfor a variety of reasons. For example, the controller may determine newcalibration settings or an update to the settings of the receiver ortransmitter based on the received signal. In one embodiment, updates tothe receiver may be provided via the transmitter using the serial bus.

By shifting the analog to digital conversion to the transmitter andhaving the transmitter provide the optical power information, a numberof advantages are achieved. First, were the analog to digital conversionperformed on the receiver, the receiver's sensitivity of the opticalsignals may be reduced, which may be particularly deleterious insituations where the signal-to-noise ratio is very low, which is oftenthe case in ring networks. Additionally, because the receiver sends ananalog signal in this embodiment, the power consumed by the receiver maybe lower than it would be if it performed analog to digital conversion.Finally, since the transmitter is able to provide the optical powerinformation to the controller, a pin may not be required forcommunication between the receiver and then controller. Instead, a pinof the transceiver may be used for communication between the transmitterand the controller. Correspondingly, the transmitter may act as ago-between for the receiver and controller. Accordingly, the transceiverchip may require one less pin than in other implementations, whichresults in large cost savings and efficiency.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

We claim:
 1. A method, comprising: an optical receiver, comprised in afirst device, receiving optical data from a second device; the opticalreceiver determining optical power of optical signals of the opticaldata; the optical receiver providing the optical power to an opticaltransmitter comprised in the first device, wherein the opticaltransmitter is configured to provide the optical power to a controllerof the first device.
 2. The method of claim 1, wherein said providingthe optical power comprises providing a voltage that indicates theoptical power.
 3. The method of claim 1, wherein said providing theoptical power comprises providing a current that indicates the opticalpower.
 4. The method of claim 1, wherein said providing the opticalpower comprises providing an analog signal that indicates the opticalpower, wherein the optical transmitter is configured to perform analogto digital conversion of the analog signal and provide a digital signalindicating the optical power to the controller of the first device. 5.The method of claim 4, wherein said providing the optical power to thetransmitter as the analog signal reduces noise for the optical receiver.6. The method of claim 1, wherein said providing the optical power isperformed over a serial bus.
 7. The method of claim 1, wherein saidproviding the optical power utilizes a serial peripheral interface (SPI)comprised in the optical receiver.
 8. The method of claim 1, wherein theoptical receiver and the optical transmitter are collocated within atransceiver.
 9. A method for determining optical power of opticalsignals, comprising: an optical transmitter receiving an analog signalindicating optical power of optical signals received by an opticalreceiver, wherein the optical transmitter and optical receiver arecomprised within a first device, wherein the optical signals arereceived by the optical receiver from an external device; the opticaltransmitter performing analog to digital conversion of the analog signalto generate digital information indicating the optical power of theoptical signals received by the optical receiver; and the opticaltransmitter providing the digital information to a controller of thefirst device.
 10. The method of claim 9, wherein the analog signalcomprises a voltage indicating the optical power of the optical signals.11. The method of claim 9, wherein the analog signal comprises a currentindicating the optical power of the optical signals.
 12. The method ofclaim 9, wherein said receiving the analog signal reduces noise for theoptical receiver.
 13. The method of claim 9, wherein said receiving theanalog signal is performed over a serial bus.
 14. The method of claim 9,wherein said receiving the analog signal utilizes a serial peripheralinterface (SPI) comprised in the optical transmitter.
 15. The method ofclaim 9, wherein the optical receiver and the optical transmitter arecollocated within a transceiver.
 16. An optical transceiver configuredfor inclusion within a first device, wherein the optical transceivercomprises: an optical receiver coupled to a photodiode, wherein theoptical receiver is configured to receive optical signals from a firstexternal device via the photodiode; an optical transmitter, wherein theoptical transmitter is configured to transmit optical signals to asecond external device using a light emitting diode (LED), wherein theoptical receiver and the optical transmitter are coupled over a serialbus; wherein the optical receiver is configured to: determine opticalpower of optical signals received from the first external device; andprovide the optical power to the optical transmitter; wherein theoptical transmitter is configured to: receive the optical power from theoptical receiver; and provide the optical power to a controller of thefirst device.
 17. The optical transceiver of claim 16, wherein theoptical receiver is configured to provide the optical power to theoptical transmitter as an analog signal that indicates the opticalpower; wherein the optical transmitter is configured to perform analogto digital conversion of the analog signal and provide a digital signalindicating the optical power to the controller of the first device. 18.The optical transceiver of claim 17, wherein said providing the opticalpower to the transmitter as the analog signal reduces noise for theoptical receiver.
 19. The optical transceiver of claim 16, wherein theoptical receiver is configured to provide a voltage to the opticaltransmitter, wherein the voltage indicates the optical power.
 20. Theoptical transceiver of claim 16, wherein the optical receiver isconfigured to provide a current to the optical transmitter, wherein thecurrent indicates the optical power.